Portable electronic devices, such as cellular telephones, laptop computers, tablet computers, pagers, and two-way radios for example, derive their portability from batteries having rechargeable cells. These batteries allow these devices to slip the surly bonds of power supplies tethered to walls and to travel wirelessly with users wherever they may go. A typical battery disposed within one of these devices may be charged and discharged hundreds of times over its lifetime. This is particularly true due to the daily reliance people increasingly place upon their personal devices.
It is known that the rechargeable batteries of many devices can be recharged wirelessly, e.g., induction-charging systems are commonly found in devices like portable motorized toothbrushes. Similarly, portable wireless communication devices and other battery-powered devices can utilize a rechargeable battery that can be recharged wirelessly. Such devices are popular due to the convenience afforded to a user by working without a wired connection. With wireless charging, the user need not connect plugs to sockets to charge a battery. Additionally, the user is able to more quickly remove the device from the charger after the battery has been charged.
While wireless charging offers an increased convenience, design issues can limit the rate at which the cells of a battery can effectively be charged. For example, thermal limitations of the system can extend the charging time or terminate charging prematurely.
It would be advantageous to have an improved wireless charging system.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.